The MIL

La
My husband and I have been married three and a half years. We come from completely different backgrounds...his mother was a drug addict when he was younger and he was pretty much raised by his grandparents. She was arrested a few times, has always struggled financially, made some very poor decisions, etc. I was raised in a highly religious, education oriented, upper middle class family. Everyone in my family--including me--has a Bachelor's or Master's degree. 
Here's the deal...no one in my family has ever judged his mother or the rest of the family at all. My Dad treats my hubby like the son he's the son he never had. He and my Dad are VERY close. My parents live 2.5 hours away, so when we are off we tend to go visit--about every other weekend.
His mother and her boyfriend just moved back to Georgia and are having to live with his grandparents because they are unable to afford a place of their own right now. They live 15 minutes from us. My hubby and I, while not rich, make decent money. We enjoy going on trips, visiting my folks, having date nights, etc. it was never a problem but now that she moved back it's like she gets upset that we aren't over there every single night and go to visit my folks...even though we go over there quite a bit. We just went last night for dinner and watched a movie with them. 
She told my husband she feels like we are treating my parents like they are "more special" than his family. Which is not true--at all. Christmas <a href="https://play.google.com/store/apps/details?id=com.glow.android.eve">Eve</a> I cooked a big dinner at our place. My parents and his family were invited. When told her alcoholic boyfriend could not come if he was drunk, she blamed it on the fact that my parents would be there. She has been giving me nasty looks lately, and whereas she used to hug me goodbye each time we left, now I have to approach her every time. It bothers me a little because she doesn't ever call me...not to wish me happy birthday, happy New Years, etc. but she calls my hubby and the rest of his family regularly.
This is the first time I have really had to deal with my mother in law on a regular basis since we've been married. Advice?